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Cope JE, Berckx F, Galinski A, Lentz J, Nagel KA, Fiorani F, Weih M. Precrop-treated soil influences wheat ( Triticum aestivum L.) root system architecture and its response to drought. FRONTIERS IN PLANT SCIENCE 2024; 15:1389593. [PMID: 38895614 PMCID: PMC11184070 DOI: 10.3389/fpls.2024.1389593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 05/22/2024] [Indexed: 06/21/2024]
Abstract
Aims Root system architecture (RSA) plays an important role in the plant's ability to sustain yield under abiotic stresses such as drought. Preceding crops (precrops) can affect the yield of the proceeding crop, partially by affecting the RSA. This experiment aims to explore the interactions between precrop identity, crop genotype and drought at early growth stages. Methods Rhizotrons, sized 60 × 80 × 3.5 cm, were used to assess the early root growth of two winter wheat (Triticum aestivum L.) genotypes, using precrop-treated soil around the seedlings and differing water regimes. The rhizotrons were automatically imaged 3 times a week to track root development. Results Precrop-treated soil affected the RSA and changes caused by the reduced water treatment (RWT) were different depending on the precrop. Largest of these was the 36% reduction in root depth after wheat, but 44% after OSR. This indicates that effects caused by the precrop can be simulated, at least partially, by transferring precrop-treated soils to controlled environments. The genotypes had differential RSA and reacted differently to the RWT, with Julius maintaining an 8.8-13.1% deeper root system compared to Brons in the RWT. In addition, the combined environmental treatment affected the genotypes differently. Conclusion Our results could help explain discrepancies found from using precrops to enhance yield as they indicate differences in the preceding crop effect when experiencing drought stress. Further, these differences are affected by genotypic interactions, which can be used to select and adapt crop genotypes for specific crop rotations, depending on the year. Additionally, we have shown a viable method of stimulating a partial precrop effect at the seedling stage in a controlled greenhouse setting using field soil around the germinated seed.
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Affiliation(s)
- Jonathan E. Cope
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Fede Berckx
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anna Galinski
- Institute of Bio- and Geosciences, Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Jonas Lentz
- Institute of Bio- and Geosciences, Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Kerstin A. Nagel
- Institute of Bio- and Geosciences, Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Fabio Fiorani
- Institute of Bio- and Geosciences, Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Martin Weih
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Voothuluru P, Wu Y, Sharp RE. Not so hidden anymore: Advances and challenges in understanding root growth under water deficits. THE PLANT CELL 2024; 36:1377-1409. [PMID: 38382086 PMCID: PMC11062450 DOI: 10.1093/plcell/koae055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 02/09/2024] [Accepted: 02/15/2024] [Indexed: 02/23/2024]
Abstract
Limited water availability is a major environmental factor constraining plant development and crop yields. One of the prominent adaptations of plants to water deficits is the maintenance of root growth that enables sustained access to soil water. Despite early recognition of the adaptive significance of root growth maintenance under water deficits, progress in understanding has been hampered by the inherent complexity of root systems and their interactions with the soil environment. We highlight selected milestones in the understanding of root growth responses to water deficits, with emphasis on founding studies that have shaped current knowledge and set the stage for further investigation. We revisit the concept of integrated biophysical and metabolic regulation of plant growth and use this framework to review central growth-regulatory processes occurring within root growth zones under water stress at subcellular to organ scales. Key topics include the primary processes of modifications of cell wall-yielding properties and osmotic adjustment, as well as regulatory roles of abscisic acid and its interactions with other hormones. We include consideration of long-recognized responses for which detailed mechanistic understanding has been elusive until recently, for example hydrotropism, and identify gaps in knowledge, ongoing challenges, and opportunities for future research.
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Affiliation(s)
- Priya Voothuluru
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
- Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211, USA
| | - Yajun Wu
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA
| | - Robert E Sharp
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
- Interdisciplinary Plant Group, University of Missouri, Columbia, MO 65211, USA
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Protto V, Bauget F, Rishmawi L, Nacry P, Maurel C. Primary, seminal and lateral roots of maize show type-specific growth and hydraulic responses to water deficit. PLANT PHYSIOLOGY 2024; 194:2564-2579. [PMID: 38217868 PMCID: PMC10980523 DOI: 10.1093/plphys/kiad675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/07/2023] [Accepted: 11/27/2023] [Indexed: 01/15/2024]
Abstract
The water uptake capacity of a root system is determined by its architecture and hydraulic properties, which together shape the root hydraulic architecture. Here, we investigated root responses to water deficit (WD) in seedlings of a maize (Zea mays) hybrid line (B73H) grown in hydroponic conditions, taking into account the primary root (PR), the seminal roots (SR), and their respective lateral roots. WD was induced by various polyethylene glycol concentrations and resulted in dose-dependent inhibitions of axial and lateral root growth, lateral root formation, and hydraulic conductivity (Lpr), with slightly distinct sensitivities to WD between PR and SR. Inhibition of Lpr by WD showed a half-time of 5 to 6 min and was fully (SR) or partially (PR) reversible within 40 min. In the two root types, WD resulted in reduced aquaporin expression and activity, as monitored by mRNA abundance of 13 plasma membrane intrinsic protein (ZmPIP) isoforms and inhibition of Lpr by sodium azide, respectively. An enhanced suberization/lignification of the epi- and exodermis was observed under WD in axial roots and in lateral roots of the PR but not in those of SR. Inverse modeling revealed a steep increase in axial conductance in root tips of PR and SR grown under WD that may be due to the decreased growth rate of axial roots in these conditions. Overall, our work reveals that these root types show quantitative differences in their anatomical, architectural, and hydraulic responses to WD, in terms of sensitivity, amplitude and reversibility. This distinct functionalization may contribute to integrative acclimation responses of whole root systems to soil WD.
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Affiliation(s)
- Virginia Protto
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, 2 place Viala, 34060 Montpellier, France
| | - Fabrice Bauget
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, 2 place Viala, 34060 Montpellier, France
| | - Louai Rishmawi
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, 2 place Viala, 34060 Montpellier, France
| | - Philippe Nacry
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, 2 place Viala, 34060 Montpellier, France
| | - Christophe Maurel
- Institute for Plant Sciences of Montpellier (IPSiM), Univ Montpellier, CNRS, INRAE, Institut Agro, 2 place Viala, 34060 Montpellier, France
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4
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Dalal M, Mansi, Mayandi K. Zoom-in to molecular mechanisms underlying root growth and function under heterogeneous soil environment and abiotic stresses. PLANTA 2023; 258:108. [PMID: 37898971 DOI: 10.1007/s00425-023-04262-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 10/06/2023] [Indexed: 10/31/2023]
Abstract
MAIN CONCLUSION The review describes tissue-specific and non-cell autonomous molecular responses regulating the root system architecture and function in plants. Phenotypic plasticity of roots relies on specific molecular and tissue specific responses towards local and microscale heterogeneity in edaphic factors. Unlike gravitropism, hydrotropism in Arabidopsis is regulated by MIZU KUSSIE1 (MIZ1)-dependent asymmetric distribution of cytokinin and activation of Arabidopsis response regulators, ARR16 and ARR17 on the lower water potential side of the root leading to higher cell division and root bending. The cortex specific role of Abscisic acid (ABA)-activated SNF1-related protein kinase 2.2 (SnRK2.2) and MIZ1 in elongation zone is emerging for hydrotropic curvature. Halotropism involves clathrin-mediated internalization of PIN FORMED 2 (PIN2) proteins at the side facing higher salt concentration in the root tip, and ABA-activated SnRK2.6 mediated phosphorylation of cortical microtubule-associated protein Spiral2-like (SP2L) in the root transition zone, which results in anisotropic cell expansion and root bending away from higher salt. In hydropatterning, Indole-3-acetic acid 3 (IAA3) interacts with SUMOylated-ARF7 (Auxin response factor 7) and prevents expression of Lateral organ boundaries-domain 16 (LBD16) in air-side of the root, while on wet side of the root, IAA3 cannot repress the non-SUMOylated-ARF7 thereby leading to LBD16 expression and lateral root development. In root vasculature, ABA induces expression of microRNA165/microRNA166 in endodermis, which moves into the stele to target class III Homeodomain leucine zipper protein (HD-ZIP III) mRNA in non-cell autonomous manner. The bidirectional gradient of microRNA165/6 and HD-ZIP III mRNA regulates xylem patterning under stress. Understanding the tissue specific molecular mechanisms regulating the root responses under heterogeneous and stress environments will help in designing climate-resilient crops.
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Affiliation(s)
- Monika Dalal
- ICAR-National Institute for Plant Biotechnology, New Delhi, 110012, India.
| | - Mansi
- ICAR-National Institute for Plant Biotechnology, New Delhi, 110012, India
- Department of Biosciences, Durham University, Durham, DH1 3LE, UK
| | - Karthikeyan Mayandi
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara, 630-0192, Japan
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Roberts JT, McCubbin TJ, Braun DM. A Plate Growth Assay to Quantify Embryonic Root Development of Zea mays. Bio Protoc 2023; 13:e4858. [PMID: 37900110 PMCID: PMC10603264 DOI: 10.21769/bioprotoc.4858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 10/31/2023] Open
Abstract
Murashige-Skoog medium solutions have been used in a variety of plant plate growth assays, yet most research uses Arabidopsis thaliana as the study organism. For larger seeds such as maize (Zea mays), most protocols employ a paper towel roll method for experiments, which often involves wrapping maize seedlings in wet, sterile germination paper. What the paper towel roll method lacks, however, is the ability to image the roots over time without risk of contamination. Here, we describe a sterile plate growth assay that contains Murashige-Skoog medium to grow seedlings starting two days after germination. This protocol uses a section of a paper towel roll method to achieve uniform germination of maize seedlings, which are sterilely transferred onto large acrylic plates for the duration of the experiment. The media can undergo modification to include an assortment of plant hormones, exogenous sugars, and other chemicals. The acrylic plates allow researchers to freely image the plate without disturbing the seedlings and control the environment in which the seedlings are grown, such as modifications in temperature and light. Additionally, the protocol is widely adaptable for use with other cereal crops. Key features • Builds upon plate growth methods routinely used for Arabidopsis seedlings but that are inadequate for maize. • Real-time photographic analysis of seedlings up to two weeks following germination. • Allows for testing of various growth conditions involving an assortment of additives and/or modification of environmental conditions. • Samples are able to be collected for genotype screening.
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Affiliation(s)
- Jason T Roberts
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri, Columbia, MO, USA
| | - Tyler J McCubbin
- Division of Plant Science and Technology, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri, Columbia, MO, USA
| | - David M Braun
- Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri, Columbia, MO, USA
- Division of Plant Science and Technology, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri, Columbia, MO, USA
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Wang Y, Wang J, Guo H, Wu X, Hao M, Zhang R. Integrative transcriptome and metabolome analysis reveals the mechanism of exogenous melatonin alleviating drought stress in maize roots. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 199:107723. [PMID: 37163805 DOI: 10.1016/j.plaphy.2023.107723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/15/2023] [Accepted: 04/25/2023] [Indexed: 05/12/2023]
Abstract
Melatonin (MT) is essential for plant development and drought adaptation. However, the molecular and metabolic mechanisms underlying MT-induced drought tolerance in maize roots remain largely unclear. Herein, we investigated the effects of MT on drought tolerance in maize roots using integrated transcriptomic and metabolomic analyses, and identified MT-induced genes and metabolites associated with drought resistance. Compared with the untreated control plants, MT application alleviated the deleterious effects of drought on roots, by decreasing the malondialdehyde level and increasing the solute potential, eventually promoting root growth. Transcriptome and metabolome analysis demonstrated that MT significantly upregulates the expression of genes related to flavonoid biosynthesis (PAL, C4H, 4CL, HCT, CHS, CHI, F3'5'H, and DFR), activates drought-responsive transcription factors (ERFs, NACs, MYBs, and bHLHs), and regulates hormone signaling-related genes, especially ethylene response factors (ERF4, ERF81, and ERF110). Moreover, MT increased the accumulation of flavonoid metabolites, particularly apigenin, luteolin, and quercetin, under drought-stress conditions. These findings were further supported by quantitative real-time polymerase chain reaction analysis and total flavonoid measurements. Altogether, our findings suggest that MT promotes maize root growth during drought by regulating flavonoid synthesis pathways, transcription factors, and plant hormone signals. This study provides new insights into the complex mechanisms by which MT enhances crop resistance to drought damage.
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Affiliation(s)
- Yifan Wang
- College of Agronomy, Northwest A&F University, Shaanxi, Yangling, 712100, China
| | - Jiarui Wang
- College of Agronomy, Northwest A&F University, Shaanxi, Yangling, 712100, China
| | - Haoxue Guo
- College of Agronomy, Northwest A&F University, Shaanxi, Yangling, 712100, China
| | - Xi Wu
- College of Agronomy, Northwest A&F University, Shaanxi, Yangling, 712100, China
| | - Miaoyi Hao
- College of Agronomy, Northwest A&F University, Shaanxi, Yangling, 712100, China
| | - Renhe Zhang
- College of Agronomy, Northwest A&F University, Shaanxi, Yangling, 712100, China.
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7
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De novo transcriptome assembly from the nodal root growth zone of hydrated and water-deficit stressed maize inbred line FR697. Sci Rep 2023; 13:1960. [PMID: 36737660 PMCID: PMC9898524 DOI: 10.1038/s41598-023-29115-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
Certain cultivars of maize show increased tolerance to water deficit conditions by maintenance of root growth. To better understand the molecular mechanisms related to this adaptation, nodal root growth zone samples were collected from the reference inbred line B73 and inbred line FR697, which exhibits a relatively greater ability to maintain root elongation under water deficits. Plants were grown under various water stress levels in both field and controlled environment settings. FR697-specific RNA-Seq datasets were generated and used for a de novo transcriptome assembly to characterize any genotype-specific genetic features. The assembly was aided by an Iso-Seq library of transcripts generated from various FR697 plant tissue samples. The Necklace pipeline was used to combine a Trinity de novo assembly along with a reference guided assembly and the Viridiplantae proteome to generate an annotated consensus "SuperTranscriptome" assembly of 47,915 transcripts with a N50 of 3152 bp in length. The results were compared by Blastn to maize reference genes, a Benchmarking Universal Single-Copy Orthologs (BUSCO) genome completeness report and compared with three maize reference genomes. The resultant 'SuperTranscriptome' was demonstrated to be of high-quality and will serve as an important reference for analysis of the maize nodal root transcriptomic response to environmental perturbations.
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8
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Juenger TE, Verslues PE. Time for a drought experiment: Do you know your plants' water status? THE PLANT CELL 2023; 35:10-23. [PMID: 36346190 PMCID: PMC9806650 DOI: 10.1093/plcell/koac324] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Drought stress is an increasing concern because of climate change and increasing demands on water for agriculture. There are still many unknowns about how plants sense and respond to water limitation, including which genes and cellular mechanisms are impactful for ecology and crop improvement in drought-prone environments. A better understanding of plant drought resistance will require integration of several research disciplines. A common set of parameters to describe plant water status and quantify drought severity can enhance data interpretation and research integration across the research disciplines involved in understanding drought resistance and would be especially useful in integrating the flood of genomic data being generated in drought studies. Water potential (ψw) is a physical measure of the free energy status of water that, along with related physiological measurements, allows unambiguous description of plant water status that can apply across various soil types and environmental conditions. ψw and related physiological parameters can be measured with relatively modest investment in equipment and effort. Thus, we propose that increased use of ψw as a fundamental descriptor of plant water status can enhance the insight gained from many drought-related experiments and facilitate data integration and sharing across laboratories and research disciplines.
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Dowd TG, Li M, Bagnall GC, Johnston A, Topp CN. Root system architecture and environmental flux analysis in mature crops using 3D root mesocosms. FRONTIERS IN PLANT SCIENCE 2022; 13:1041404. [PMID: 36589101 PMCID: PMC9800027 DOI: 10.3389/fpls.2022.1041404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
Current methods of root sampling typically only obtain small or incomplete sections of root systems and do not capture their true complexity. To facilitate the visualization and analysis of full-sized plant root systems in 3-dimensions, we developed customized mesocosm growth containers. While highly scalable, the design presented here uses an internal volume of 45 ft3 (1.27 m3), suitable for large crop and bioenergy grass root systems to grow largely unconstrained. Furthermore, they allow for the excavation and preservation of 3-dimensional root system architecture (RSA), and facilitate the collection of time-resolved subterranean environmental data. Sensor arrays monitoring matric potential, temperature and CO2 levels are buried in a grid formation at various depths to assess environmental fluxes at regular intervals. Methods of 3D data visualization of fluxes were developed to allow for comparison with root system architectural traits. Following harvest, the recovered root system can be digitally reconstructed in 3D through photogrammetry, which is an inexpensive method requiring only an appropriate studio space and a digital camera. We developed a pipeline to extract features from the 3D point clouds, or from derived skeletons that include point cloud voxel number as a proxy for biomass, total root system length, volume, depth, convex hull volume and solidity as a function of depth. Ground-truthing these features with biomass measurements from manually dissected root systems showed a high correlation. We evaluated switchgrass, maize, and sorghum root systems to highlight the capability for species wide comparisons. We focused on two switchgrass ecotypes, upland (VS16) and lowland (WBC3), in identical environments to demonstrate widely different root system architectures that may be indicative of core differences in their rhizoeconomic foraging strategies. Finally, we imposed a strong physiological water stress and manipulated the growth medium to demonstrate whole root system plasticity in response to environmental stimuli. Hence, these new "3D Root Mesocosms" and accompanying computational analysis provides a new paradigm for study of mature crop systems and the environmental fluxes that shape them.
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10
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Robertson SM, Sakariyahu SK, Bolaji A, Belmonte MF, Wilkins O. Growth-limiting drought stress induces time-of-day-dependent transcriptome and physiological responses in hybrid poplar. AOB PLANTS 2022; 14:plac040. [PMID: 36196395 PMCID: PMC9521483 DOI: 10.1093/aobpla/plac040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 08/25/2022] [Indexed: 06/16/2023]
Abstract
Drought stress negatively impacts the health of long-lived trees. Understanding the genetic mechanisms that underpin response to drought stress is requisite for selecting or enhancing climate change resilience. We aimed to determine how hybrid poplars respond to prolonged and uniform exposure to drought; how responses to moderate and more severe growth-limiting drought stresses differed; and how drought responses change throughout the day. We established hybrid poplar trees (Populus × 'Okanese') from unrooted stem cutting with abundant soil moisture for 6 weeks. We then withheld water to establish well-watered, moderate and severe growth-limiting drought conditions. These conditions were maintained for 3 weeks during which growth was monitored. We then measured photosynthetic rates and transcriptomes of leaves that had developed during the drought treatments at two times of day. The moderate and severe drought treatments elicited distinct changes in growth and development, photosynthetic rates and global transcriptome profiles. Notably, the time of day of sampling produced the strongest effect in the transcriptome data. The moderate drought treatment elicited global transcriptome changes that were intermediate to the severe and well-watered treatments in the early evening but did not elicit a strong drought response in the morning. Stable drought conditions that are sufficient to limit plant growth elicit distinct transcriptional profiles depending on the degree of water limitation and on the time of day at which they are measured. There appears to be a limited number of genes and functional gene categories that are responsive to all of the tested drought conditions in this study emphasizing the complex nature of drought regulation in long-lived trees.
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Affiliation(s)
- Sean M Robertson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | | | - Ayooluwa Bolaji
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3E 3R2, Canada
| | - Mark F Belmonte
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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11
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Crop Root Responses to Drought Stress: Molecular Mechanisms, Nutrient Regulations, and Interactions with Microorganisms in the Rhizosphere. Int J Mol Sci 2022; 23:ijms23169310. [PMID: 36012575 PMCID: PMC9409098 DOI: 10.3390/ijms23169310] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/03/2022] [Accepted: 08/17/2022] [Indexed: 12/03/2022] Open
Abstract
Roots play important roles in determining crop development under drought. Under such conditions, the molecular mechanisms underlying key responses and interactions with the rhizosphere in crop roots remain limited compared with model species such as Arabidopsis. This article reviews the molecular mechanisms of the morphological, physiological, and metabolic responses to drought stress in typical crop roots, along with the regulation of soil nutrients and microorganisms to these responses. Firstly, we summarize how root growth and architecture are regulated by essential genes and metabolic processes under water-deficit conditions. Secondly, the functions of the fundamental plant hormone, abscisic acid, on regulating crop root growth under drought are highlighted. Moreover, we discuss how the responses of crop roots to altered water status are impacted by nutrients, and vice versa. Finally, this article explores current knowledge of the feedback between plant and soil microbial responses to drought and the manipulation of rhizosphere microbes for improving the resilience of crop production to water stress. Through these insights, we conclude that to gain a more comprehensive understanding of drought adaption mechanisms in crop roots, future studies should have a network view, linking key responses of roots with environmental factors.
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12
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Le Thanh T, Hufnagel B, Soriano A, Divol F, Brottier L, Casset C, Péret B, Doumas P, Marquès L. Dynamic Development of White Lupin Rootlets Along a Cluster Root. FRONTIERS IN PLANT SCIENCE 2021; 12:738172. [PMID: 34557216 PMCID: PMC8452988 DOI: 10.3389/fpls.2021.738172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/19/2021] [Indexed: 05/30/2023]
Abstract
White lupin produces cluster roots in response to phosphorus deficiency. Along the cluster root, numerous short rootlets successively appear, creating a spatial and temporal gradient of developmental stages that constitutes a powerful biological model to study the dynamics of the structural and functional evolution of these organs. The present study proposes a fine histochemical, transcriptomic and functional analysis of the rootlet development from its emergence to its final length. Between these two stages, the tissue structures of the rootlets were observed, the course of transcript expressions for the genes differentially expressed was monitored and some physiological events linked to Pi nutrition were followed. A switch between (i) a growing phase, in which a normal apical meristem is present and (ii) a specialized phase for nutrition, in which the rootlet is completely differentiated, was highlighted. In the final stage of its determinate growth, the rootlet is an organ with a very active metabolism, especially for the solubilization and absorption of several nutrients. This work discusses how the transition between a growing to a determinate state in response to nutritional stresses is found in other species and underlines the fundamental dilemma of roots between soil exploration and soil exploitation.
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13
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Dowd TG, Braun DM, Sharp RE. Maize lateral root developmental plasticity induced by mild water stress. II: Genotype-specific spatio-temporal effects on determinate development. PLANT, CELL & ENVIRONMENT 2020; 43:2409-2427. [PMID: 32644247 DOI: 10.1111/pce.13840] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 06/11/2023]
Abstract
Maize lateral roots exhibit determinate growth, whereby the meristem is genetically programmed to stop producing new cells. To explore whether lateral root determinacy is modified under water deficits, we studied two maize genotypes (B73 and FR697) with divergent responses of lateral root growth to mild water stress using an experimental system that provided near-stable water potential environments throughout lateral root development. First-order laterals of the primary root system of FR697 exhibited delayed determinacy when grown at a water potential of -0.28 MPa, resulting in longer and wider roots than in well-watered (WW) controls. In B73, in contrast, neither the length nor width of lateral roots was affected by water deficit. In water-stressed FR697, root elongation continued at or above the maximum rate in WW roots for 3 days longer, and was still 45% of maximum when WW roots approached their determinate length. Maintenance of root elongation was associated with sustained rates of cell production. In addition, kinematic analyses showed that reductions in tissue expansion rates with aging were delayed in the longitudinal, radial and tangential planes throughout the root growth zone. Thus, this study reveals large genotypic differences in the interaction of water stress with developmental determinacy of maize lateral roots.
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Affiliation(s)
- Tyler G Dowd
- Division of Plant Sciences, University of Missouri, Columbia, Missouri, USA
- Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, USA
| | - David M Braun
- Division of Plant Sciences, University of Missouri, Columbia, Missouri, USA
- Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, USA
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
| | - Robert E Sharp
- Division of Plant Sciences, University of Missouri, Columbia, Missouri, USA
- Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri, USA
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14
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Sharma NK, Gupta SK, Dwivedi V, Chattopadhyay D. Lignin deposition in chickpea root xylem under drought. PLANT SIGNALING & BEHAVIOR 2020; 15:1754621. [PMID: 32290771 PMCID: PMC8570712 DOI: 10.1080/15592324.2020.1754621] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In our recent publication, we have shown that a member of the Laccase family, LACCASE2 (LAC2) acted as a negative regulator of lignin deposition in the root xylem tissue of Arabidopsis thaliana. LAC2 messenger RNA (mRNA) level was post-transcriptionally regulated by microRNA 397b, which showed increased expression under water and phosphate deficiency, resulting in the downregulation of LAC2 expression In this report, we have investigated root growth and lignin deposition in an economically important legume crop chickpea (Cicer arietinum L.) in response to natural drought in soil-grown condition. In contrast to the growth retardation of Arabidopsis root in mannitol-supplemented medium, chickpea root showed an increase in length in low soil moisture condition. Lignin estimation in the primary root showed an increase in lignin content, which was substantiated by staining of root xylem. Drought treatment enhanced the expression of four out of six LAC genes tested, while the expression of two was downregulated. Our preliminary study indicateed a molecular mechanism of lignin deposition in chickpea root xylem during drought.
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Affiliation(s)
| | | | - Vikas Dwivedi
- National Institute of Plant Genome Research, New Delhi, India
| | - Debasis Chattopadhyay
- National Institute of Plant Genome Research, New Delhi, India
- CONTACT Debasis Chattopadhyay National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi110067, India
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15
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Abstract
Roots provide the primary mechanism that plants use to absorb water and nutrients from their environment. These functions are dependent on developmental mechanisms that direct root growth and branching into regions of soil where these resources are relatively abundant. Water is the most limiting factor for plant growth, and its availability is determined by the weather, soil structure, and salinity. In this review, we define the developmental pathways that regulate the direction of growth and branching pattern of the root system, which together determine the expanse of soil from which a plant can access water. The ability of plants to regulate development in response to the spatial distribution of water is a focus of many recent studies and provides a model for understanding how biological systems utilize positional cues to affect signaling and morphogenesis. A better understanding of these processes will inform approaches to improve crop water use efficiency to more sustainably feed a growing population.
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Affiliation(s)
- José R. Dinneny
- Department of Biology, Stanford University, Stanford, California 94305, USA
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16
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Nieves-Cordones M, García-Sánchez F, Pérez-Pérez JG, Colmenero-Flores JM, Rubio F, Rosales MA. Coping With Water Shortage: An Update on the Role of K +, Cl -, and Water Membrane Transport Mechanisms on Drought Resistance. FRONTIERS IN PLANT SCIENCE 2019; 10:1619. [PMID: 31921262 PMCID: PMC6934057 DOI: 10.3389/fpls.2019.01619] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 11/18/2019] [Indexed: 05/21/2023]
Abstract
Drought is now recognized as the abiotic stress that causes most problems in agriculture, mainly due to the strong water demand from intensive culture and the effects of climate change, especially in arid/semi-arid areas. When plants suffer from water deficit (WD), a plethora of negative physiological alterations such as cell turgor loss, reduction of CO2 net assimilation rate, oxidative stress damage, and nutritional imbalances, among others, can lead to a decrease in the yield production and loss of commercial quality. Nutritional imbalances in plants grown under drought stress occur by decreasing water uptake and leaf transpiration, combined by alteration of nutrient uptake and long-distance transport processes. Plants try to counteract these effects by activating drought resistance mechanisms. Correct accumulation of salts and water constitutes an important portion of these mechanisms, in particular of those related to the cell osmotic adjustment and function of stomata. In recent years, molecular insights into the regulation of K+, Cl-, and water transport under drought have been gained. Therefore, this article brings an update on this topic. Moreover, agronomical practices that ameliorate drought symptoms of crops by improving nutrient homeostasis will also be presented.
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Affiliation(s)
- Manuel Nieves-Cordones
- Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura–CSIC, Murcia, Spain
- *Correspondence: Manuel Nieves-Cordones,
| | - Francisco García-Sánchez
- Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura–CSIC, Murcia, Spain
| | - Juan G. Pérez-Pérez
- Centro para el Desarrollo de la Agricultura Sostenible (CDAS), Instituto Valenciano de Investigaciones Agrarias (IVIA), Valencia, Spain
| | - Jose M. Colmenero-Flores
- Instituto de Recursos Naturales y Agrobiología, Spanish National Research Council (CSIC), Sevilla, Spain
| | - Francisco Rubio
- Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura–CSIC, Murcia, Spain
| | - Miguel A. Rosales
- Instituto de Recursos Naturales y Agrobiología, Spanish National Research Council (CSIC), Sevilla, Spain
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